My gliders like the little dollhouse style floor toys, we have a pirate ship, a barn, a castle, a rainforest scene and a giant house. Sometimes I put them in the bottom of the cage, but I like to use them in the tent more often for them to hide out in and jump on/off.
I try to stay away from rattly noisey toys as the gliders are close to my bedroom and they'd keep us up all night if I left anything like that in their cage!
My gliders tend to like toys that have treats hidden in them. Otherwise, they'll explore them when they are new, but they get bored of them quickly. So, anything with hidden areas I can drop treats into, or little spaces for dropping a dollop of yogurt gets their attention!